<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        body{
            font-family: 'asss';
        }
    </style>
</head>
<body>
<div>dswedd</div>
<script>

    var each = function (ary ,callback) {
        for(var i = 0,l=ary.length;i<l;i++){
            callback.call(ary[i],i,ary[i]);
        }
    }
    each([1,2,3],function (i,n) {
       console.log(i,n);
    })
</script>
</body>
</html>